BAXI 80 Eco --- NO HEATING_HELP!

[tona955]

Hi All
New to this forum..so be gentle.

1, Baxi 80 eco DHW OK but no Heating.
2, New house and boiler was pre-installed.
3, Worked fine for a week or so.
4, System pressure just over 1Bar and steady with no leaks.
5, Turned off mains water, boiler and gas supply for 3 weeks holiday.
6, Heating Temp control on boiler turned fully on (max).
7, No external room stat, loop wire installed on terminal block.

Searched forum and learned poss temp stat issue, but I can not see a black or red mini reset switch, i see the copper pipe (Left side) leading up to the burner with two connectors on it, top one (Temp Sensor)has two red leads running from it and the bottom one (Safety Limit Thermostat)has two blue leads, but no reset switch.

The only way I can get it to fireup is as follows.

In front of the Hydraulic Outlet assembly there is the Pressure Differential assembly, this unit has a 3-Way Valve microswitch, when the hot water is demanded a plunger comes out and activates this switch, it returns when the hot water tap is turned off...well, if i keep this switch activated the heating fires up and stays on until i release the switch.

Hot water seems to work fine on demand.

The only thing I did was turn the water mains off for the past 3 weeks as i was away, now when i turn the hot or cold tap on (Bathroom of kitchen taps including bath) the pressure is very high for a few seconds and then its normal...did i open the water mains tap to much or not enough.

I am by no means a heating engineer more a computer techi but I did browse through the boiler manual.
Many thanks in advance for your help and support.
Kind regards
Tona955--Edinburgh.

 

[Slugbabydotcom]

Its not the limit stat .... The HW wouldn't work. The reset button is very small and smack in between the 2 wires BTW

Don't mess about with the Pressure differential switch. Thats for HW only.

Check call for heat. You are looking for continuity on terminals 3 and 4 of the timer. No continuity and the timer either isnt turned on or its knackered. In which case you can link across 3 and 4 to make it work.

Next suspect on list is CH sensor.

 

[tona955]

WOW!
Are you realy in Pakistan...I am impressed..where abouts in PK..

Many thanks for your prompt response, I shall check as you suggested later today and get back on teh forum.

Regards and Allah Hafiz
Tona955

 

[Agile]

If the CH sensor was low resistance it would run pump but not fire up.

If CH sensor was open circuit then it would flash one of the panel lights.

The next question will be is the pump running when there is a call for heat assuming none of the panel lights are flashing?

If not then the timeclock needs checking as above, quite a common fault. If thats OK then if you have an external room stat then that will be the likely fault.

Tony

 

[tona955]

Hi,

1, Only the power on light is on solid green.
2, When hot water is demanded the Orange flame LED is on solid.

The terminals 3 & 4? I take it you mean on the PCB on terminal block M2 (upper Right most side on PCB) this is linked directly to the microswitch on the 3-Way assembly valve, no continuity on meter until i depress the microswitch.

I removed the temp stat and whilst i could not see a micro reset switch, I do get continuity on this sensor.

The pump does not run until I demand hot water or force the CH on by depressing the 3-way micro switch.

You mentioned a timer...where is this unit as on the front panel right most side, I just have a blank circle hole, I do not have a room stat and eth CH temp dial is set to MAX.

Hope this helps, thanks once again.
Tona

 

[tonybhoy]

You must have an external timer then?

 

[tona955]

Hi
Thanks for the prompt response.

No, timers at all in the house, the only external cables going into the boiler is the mains cable.

I do have a digital timer/room stat device but it was a spare from my previous house, if this is what i am missing where would this unit be connected into the boiler.

Cheers

 

[tonybhoy]

Depends on what type but it is usually connected to the boiler terminal strip where the link would have been for external thermostats.

 

[Agile]

Hi,

The pump does not run until I demand hot water or force the CH on by depressing the 3-way micro switch.

Tona

Please think about that! You are NOT forcing the heating to be on!

You are forcing the HOT WATER ON but as the diverter valve is in the wrong position the heat goes into the rads!

Your fault is that the boiler is not responding to a call for CH .

Tony


PS I think Slug was refering to the contacts on the built in timer!!!

 

[tona955]

Hi All,

OK, I have a LANDIS & GYR RWB100 timer clock and also a siemens RDD10.1 which i would like to connect up to the boiler.

I wired up the timer as per instructtion manual but it does not start the heating when requested, perhaps i have not connected correctly.

The back connector plate has 6 connectors on it labeles: N-L-1-2-3-4, i connected teh mains onto N and L and used terminals 3&4 to go to the boiler PCB terminals 1&2 as the external control...
Is this the correct way to connect this? also where does the room stat connect to then which has 3 connectors on it labeled: Q11-Q14-Q12.

Would really appreciate some help.

Thanks again.
PS am i just better buying a machinical dial clock from Screwfix and using my Siemens room stat? I'd rather have the 7 day timer.
Cheers

 

[tona955]

Hi All,

OK, I have a LANDIS & GYR RWB100 timer clock and also a siemens RDD10.1 which i would like to connect up to the boiler.

I wired up the timer as per instructtion manual but it does not start the heating when requested, perhaps i have not connected correctly.

The back connector plate has 6 connectors on it labeles: N-L-1-2-3-4, i connected teh mains onto N and L and used terminals 3&4 to go to the boiler PCB terminals 1&2 as the external control...
Is this the correct way to connect this? also where does the room stat connect to then which has 3 connectors on it labeled: Q11-Q14-Q12.

Would really appreciate some help.

Thanks again.
PS am i just better buying a machinical dial clock from Screwfix and using my Siemens room stat? I'd rather have the 7 day timer.
Cheers

 

[tona955]

ANYBODY?

I have another quick question.

If I stick in a loop wire into the external control terminals the boiler heating side should fire up but it does not.

Is there anything else I could try or do I suspect the PCB?
Thanks again

 

[Agile]

I certainly dont have time to look up all the details to give you specific instructions on wiring it up properly.

Perhaps some of the retired people might be able to do that.

If not then the obvious advice is to call in someone competent to do it for you.

Tony

 

[tona955]

Hi,
Thanks for your response, I do appreciate that everyone is busy.

I did speak to the support chaps for the timer control and got the correct wiring diagram, I was just wanting to know if this external link should start up the heating system.
Cheers